Control system for stand-off functioning of a projectile in flight over a target area



1963 .1. BROTHERS CONTROL SYSTEM FOR STAND-OFF FUNCTIONING OF A PROJECTILE IN FLIGHT OVER A TARGET AREA Filed July 5, 1966 IN VEN'TOR.

United States Patent 01 hoe 3,416,448 Patented Dec. 17, 1968 3,416,448 CONTROL SYSTEM FOR STAND-OFF FUNCTION- IN G OF A PROJECTILE IN FLIGHT OVER A TAR- GET AREA Jack Brothers, Succasunna, N.J., assignor to the United States of America as represented by the Secretary of the Army Filed July 5, 1966, Ser. No. 562,918 5 Claims. (Cl. 102-56) ABSTRACT OF THE DISCLOSURE A small missile carried in an open cavity in the forward end of a larger explosive projectile body in flight is projected or driven ahead at a higher speed along the normal trajectory or flight path on a lanyard cord to precede the projectile by a distance determined by the length of the lanyard which is sufficient to position the projectile over a target area as the missile strikes ground. When the lanyard cord becomes taut in flight it moves an arming switch element, with which it is connected in the projectile, to effect arming thereof, and when the missile strikes it provides an electric firing current through the lanyard and the switch to function or fire the projectile.

This invention relates to projectiles of the explosive type, and more particularly to projectiles of that type adapted for functioning or bursting in air at a predetermined distance from a ground target.

Heretofore, the problem of functioning a projectile in flight directly on or at a predetermined distance from a target has been solved in various ways, none of which are believed to be the best, and include air burst by settable time fuzing or proximity fuzing, extensible mechanical probes, and by direct hits on military targets.

The old ways were unsatisfactory because direct hits by conventional projectiles are difficult to produce since the projectile must impact ground to function. If the impact is not directly on the target the fire is often ineffective.

Even the most accurate time fuzes do not provide the pinpoint-accuracy required for an air burst to be effective against entrenched targets. Proximity fuzes are extremely expensive and they are sensitive to spurious as well as true signals, making them susceptible to jamming or ineffective functioning, and extensible probes provide insuflicient standofl.

It is therefore an object of this invention to provide an improved explosive projectile that is effective and accurate for air burst at any predetermined distance above ground at the target area.

It is also an object of this invention to provide an improved explosive projectile that is equally effective against prone, advancing or entrenched military personnel, and against which countermeasures are extremely diflicult if not impossible.

The invention is embodied as a fin-stabilized projectile capable of air burst due to fuze initiation by a sensor which precedes the projectile in flight.

In accordance with one form of the invention, a small contact sensitive lead missile is ejected from the projectile on a lanyard which is a fuze line, electric line or a mechanical cord for actuating a detonator in the shell on contact of the lead missile with the ground in the target area. The length of the lanyard determines the height of the burst above ground. The projectile contains a detonator and an electrical circuit consisting of an electrical switch which arms the fuze by connecting the contactsensitive lead missile to the electric detonator by means of the lanyard.

The invention will further be understood from the following description when considered with reference to the accompanying drawing, and its scope is pointed out in the appended claims.

In the drawing FIG. 1 is a view in elevation of the proectile in flight and about to be detonated by the lead missile contacting the ground in accordance with the invention and FIG. 2 is a cross sectional view of the forward end of a projectile showing details of the invention.

Referring to the drawing, a projectile 5 is in flight over the trajectory 6 from a launching gun 7, on the earth or ground 8 to a distinct ground target such as a trench 9, for detonation a predetermined distance D from the target or ground which is determined by the length of a lanyard 10 attached to the lead missile 11. The lanyard 10 in the present example, is an electric cord connected with a piezoelectric or like voltage generating device 12 in the forward end of the missile 11. The lanyard is wound in a coil 14 in an open ended cavity 15 in the forward tapered or conical end of the projectile casing 5A which cavity also houses the lead missile with the finned shaft or tail end 16 extending into a central Well 17 at the bottom or rear end of which is provided an explosive charge or suitable pneumatic or mechanical device 20 for ejecting the missile. The conventional explosive train provided in the projectile comprises a booster charge 24, a lead cup assembly or fuzeline 25, an electrical detonator or fuze 22, and an arming switch 21 connected with the lanyard 10 to be pivoted thereby into electrical contact with the detonator 22.

0peration.Prior to firing, the projectile 5 contains all components. When fired, the projectile leaves the launcher 7 and follows the trajectory 6, at a predetermined time or point along the trajectory the lead missible 11 is ejected from the projectile by the missile ejector 20. The lead missile has acre-ballistic characteristics superior to those of the projectile and it therefore leads the projectile like a dog on a leash proceeding ahead until the lanyard 10 and 14 becomes taut and arms the fuze or detonator by closing the arming switch 21 against the detonator 22. In the event that the lead missile leaves the trajectory along which the projectile is flying, a restoring force is exerted by the taut lanyard on the lead missile thru a universal joint 26 steering the lead missile back to the projectiles trajectory 6. The restoring force diminishes as the lead missiles trajectory approaches the projectiles trajectory. It is conceivable that the lead missiles trajectory will not coincide exactly with the projectiles trajectory, but it will be close enough to make the device useful.

It will be seen that an extensible probe is limited in length during flight. The lead missile concept is superior because there is greater latitude for standoff distance. Whereas the extensible probe has been limited to a few feet by practical considerations, the lead missile is limited by practical considerations to less than 200 feet. The intended scope of use of the lead missile is well within this anticipated limit and therefore this device may be equally effective against prone, advancing or entrenched military units.

When the lead missile strikes a target or ground it sends a mechanical, electrical or chemical signal back through the lanyard to the explosive train in the projectile, functioning it in mid-air.

As shown in FIG. 2 the lead missile 11 is contact-sensitive. Its contact sensitivity can be mechanical, that is, contact suddenly makes the lanyard slack; or chemical, that is, contact initiates an explosive train in the lead missile which flashes back to the projectile through the lanyard; or it can be electrical in several ways such as the piezo-electric element 12 in the lead unissile which is energized by contact or an electrical switch in the lead missile which closes on contact and sends an electrical Signal back through the lanyard to the projectile.

The missile ejector 20 can be an explosive change which propels the lead missile from the projectile; or it can be a pneumatic device which ejects the lead missile by encapsulated air pressure; or it can be a mechanical device such as a pre-loaded spring which ejects the lead missile at the appropriate time.

I claim:

1. A stabilized air-brust projectile having an elongated cylindrical casing with a tapered forward end and a forwardly-opening cavity in said end, a relatively-smaller missile device including an electrical impact sensor mounted for ejection forwardly at a higher speed from said cavity to precede said projectile in flight along its curved trajectory over a target area before impacting ground at a point forwardly thereof, an ejector device in said cavity operable to effect said ejection of the sensor missile device at a predetermined point on said trajectory and at said higher speed whereby the missile device gains distance from the projectile in flight following ejection, a lanyard-type connecting cord between the sensor missile device and the projectile for limiting the distance gained by the missile device to permit the projectile to be in a position over said target area as the missile device and sensor reach the ground impacting point in flight along said trajectory, said connecting cord being further connected and adapted to apply arming movement to said projectile and to translate a signal from the sensor to the projectile on impact to effect detonation and air-burst of said projectile.

2. A stabilized air-brust projectile having a cylindrical casing with a tapered conical tapered end and an opening in said end, an inner cavity communicating with said opening, a finned lead missile housed in said cavity and carrying an impact sensor therein, said missile being mounted to be ejected through said opening in response to a propelling force applied thereto, means for applying said force to said missile at a predetermined point in the missile trajectory in flight and in magnitude to speed the missile ahead thereby to precede the projectile in flight, means including a signal-conveying lanyard cord connecting the missile to the projectile and restraining said missile to precede the projectile along the trajectory by a distance equal to the desired air-burst distance above a tanget area with the missile impacting ground, means providing an explosive train in said projectile connected with said cord for receiving an initiating signal therethrough, and detonator means responsive to impact of said missile with ground and signal transmission through said cord from said sensor for initiating said train and effecting said air-burst.

3. A stabilized air-burst projectile as defined in claim 2, wherein the lanyard cord includes an electrical circuit connection for transmitting the detonating signal, and wherein the sensor device of the lead missile includes a piezo-electric type signal generator responsive to impact and connected to apply a detonating signal pulse through said circuit connection to said explosive train in response to the missile impacting ground.

4. A stabilized air-burst projectile as defined in claim 2, wherein the explosive train includes an electric detonator provided with an arming switch connected with the lanyard cord to be moved in response to ejection of the lead missile to the full extent of the cord, and wherein the lead missile is provided with an explosive charge as the means for applying the propelling force thereto for eifecting ejection thereof from the cavity and the projectile.

5. A stabilized air-burst projectile as defined in claim 2, wherein the lanyard cord is initially coiled in said cavity and connected with a movable arming element for the explosive train to move it to an armed position upon full extension of the cord in flight, and wherein said cord is electrically connected between the electrical sensor and the detonator means whereby a train-initiating electrical signal is transmitted on impact from said sensor through said cord to said detonator means to initiate detonation of said train and air-burst of the projectile at said desired distance from and above the target area.

References Cited UNITED STATES PATENTS 1,309,708 7/1919 Velo l027.4 1,318,926 10/1919 Settle 102 -7.4 X 1,318,954 10/1919 Barlow l027.4 1,406,633 2/1922 Frisk l027.4 2,293,817 8/1942 Gruver l027.4 2,333,558 11/1943 Gay l027.4 2,849,957 9/ 1958 Kuller et al. l0256 X 3,173,365 3/1965 Battaglini l027.4 3,306,199 2/1967 Karin et al. l027.4

BENJAMIN A. BORCHELT, Primary Examiner.

J. FOX, Assistant Examiner.

US. Cl. X.R. 

